The invention relates generally to the field of computer aided design and geographic information systems, and in particular to a method of calculating sight distance along a virtual reality based model.
Computer aided design (CAD) applications are used for both small and large scale products. For small scale projects, typically all the surfaces, shapes and interactions are defined by the user, and the application may generate a detailed 3 dimensional (3D) model which is viewable from any angle. The ability to view the model from any angle, effectively interacting with the model, is a key component in a virtual reality system.
A geographic information system (GIS) is a system for creating, storing, analyzing and managing spatial data and their associated attributes. Preferably a GIS is embodied in a computer system capable of integrating, storing, editing, analyzing, sharing, and displaying geographically-referenced information. In a typical embodiment a GIS is a tool that allows users to create interactive queries, analyze the spatial information, and edit data.
LandXML is an extensible markup language data file format containing civil engineering design and survey measurement data commonly used in the land development and civil engineering industries. LandXML files thus comprise a data format uniquely suited to large scale projects. LandXML is rapidly becoming the file format of choice for sharing and archiving of land design data.
Light detection and ranging (LIDAR) is an optical remote sensing technology that measures properties of scattered light to find range and/or other information of a distant target. A typical LIDAR model is constituted of a cloud of points with their exact distance and location in relation to the LIDAR device.
Commercially, large scale projects on the order of civil engineering or land surveying projects have been accomplished with GIS systems. There is often a need to calculate sight distance in design of civil engineering projects such as road surface design. Sight distance is important for both calculating a safe maximum speed, approving road access and many other uses. Sight distance includes, without limitation, stopping distance, passing sight distance, sight distance triangle evaluation at at-grade intersections and sight distance required to perform evasive action.
Civil engineering projects would thus be greatly enhanced by an ability to evaluate sight distances along a planned path, preferably taking into account any intervening objects.